Vajont Dam: Difference between revisions

The Vajont Dam (or Vaiont Dam^[2]) is a dam completed in 1959 in the valley of the Vajont river under Monte Toc, 100 km north of Venice, Italy. It was one of the highest dams in the world measuring 262 metres (860 ft) high, 27 metres (89 ft) thick at the base and 3.4 metres (11 ft) at the top.

Its 1963 overtopping during initial filling was caused by the lack of consideration by the designers for the geological instability of the mountain on the southern side of the basin. Warning signs and negative appraisals during the early stages of the filling were ignored; the attempt to complete the filling led to a rapid landslide, causing a seiche wave which brought massive flooding and destruction to the area below, wiping several villages away completely and killing 2,000 people.

On 12 February 2008, while launching the International Year of Planet Earth, UNESCO cited the Vajont Dam tragedy as one of the five worst man-made disasters, caused by "the failure of engineers and geologists." ^[3]

SADE (Società Adriatica di Elettricità en: Adriatic Energy Corporation), the company building the dam, was the monopolist for electricity production and distribution in North-Eastern Italy under the Fascist regime; its owner, Giuseppe Volpi di Misurata, was Mussolini's Minister of Finances for several years. In its struggle to increase production and support Italy's industrialization, already in the 1920's the company conceived the bold idea of a dam in the gorge of the Vajont river, which would have been the tallest in the world. The company exploited the confusion after Mussolini's fall and Italy's switch of sides in World War II to get the project authorized on 15 October 1943.

The dam and basin were meant to be at the centre of a complex system of water management, in which water would have been led to the basin from nearby valleys and artificial basins located at higher levels, thanks to tens of kilometres of cement pipes and even pipe-bridges across valleys. Due to the 1963 disaster and to smaller scale landslides in other basins in the zone, the system never actually operated.

After the end of the war, the project resumed, and in the 1950's SADE—its monopoly having been confirmed by post-Fascist governments—bought out the terrains, in the face of growing opposition by the local communities of Erto and Casso, the two villages in the valley, which was overcome thanks to the support of the Italian government and police forces. The management of SADE told the public that the geology of the gorge had been studied, including analysis of ancient landslides, and that the mountain was believed to be sufficiently stable. In 1957, construction work started; however, in 1959, while building a new road on the side of Monte Toc, shifts and fractures in the rock were noticed, which led to studies in which three different experts separately told SADE that the entire side of Monte Toc was unstable and would have likely collapsed into the basin if the filling had been completed. ^[4]

The head designers and the managers of SADE ignored the negative studies; this has been attributed to the need to meet deadlines required to receive public funding, and to activate the plant before the soon-to-be-approved nationalization of electricity production, so to obtain the highest possible compensation from the State. In October 1959 construction was roughly completed, and in February 1960 SADE was authorized to start the filling by the public authorities.

Throughout the summer of 1960, minor landslides and earth movements were noticed; however instead of heeding these warning signs, the Italian government chose to sue the handful of journalists reporting the problems for "undermining the social order."

On 4 November 1960, with the level of the basin at about 190 metres of the planned 262, a landslide of about 800,000 cubic metres collapsed into the lake. SADE stopped the filling, lowered the level by about 50 metres and started to build an artificial gallery in the basin in front of Monte Toc, to keep the basin usable even after the expected further landslides would have broken it into two parts. ^[5]

In October 1961, after the completion of the gallery, SADE restarted the filling under controlled monitoring. In April and May 1962, with the basin at 215 metres, the people of Erto and Casso reported five earthquakes of the fifth grade of the Mercalli scale, though SADE downplayed their importance. ^[6] SADE was then authorized to complete the filling up to the maximum level.

In July 1962, SADE's own engineers reported the results of model-based experimentations on the effects of further landslides into the lake, which prospected a devastating disaster if they had happened after the basin had been completely filled. The management decided to ignore these results as well.

In March 1963, the dam was transferred to the newly constituted public company for electricity, ENEL, but the management remained the same. In the following summer, with the basin almost completely filled, slides, shakes and movements of the ground were continuously reported by the scared population. In the single day of 15 September, the entire side of the mountain moved down by 22 centimetres. On 26 September, SADE decided to slowly empty the basin down to the level of 240 metres, but in early October the collapse of the mountain looked unavoidable, as it moved by almost one metre a day. However, no warning or displacement order was ever issued to the population.

On 9 October 1963 at approximately 10:35pm, the combination of the drawing-down of the reservoir and heavy rains triggered an enormous landslide of about 260 million cubic metres of forest, earth, and rock, which fell into the reservoir at up to 110 km per hour (68 mph). The resulting displacement of water caused 50 million cubic metres of water to overtop the dam in a 250-metre high wave.^[1] Despite this, the dam's structure was largely undamaged — the top metre or so of masonry was washed away, but the basic structure remained intact.

However, the flooding caused by the landslide, falling into the Piave valley, destroyed the villages of Longarone, Pirago, Rivalta, Villanova and Faè, killing 1,450 people and turning the land below into a flat plain of mud. Many small villages in the territory of Erto e Casso and the village of Codissago, near Castellavazzo, were largely wrecked. Estimates of the dead range from 1900 to 2500 people, and about 350 families were completely wiped away. Most of the few survivors were children or emigrants who had lost all their near and far relatives and their friends at the same time, as well as their home and belongings. Damage was also caused by the air displacement from the immense "splash" in surrounding villages.

Immediately after the disaster, the government (who now owned the dam), politicians and public authorities insisted on attributing the tragedy to an unexpected and unavoidable natural event.

The debate on newspapers was heavily influenced by politics, since the left-wing paper L'Unità was the first to denounce the responsibilities of the management and government. The newspaper in the years before carried a number of articles by Tina Merlin who inquired on the irresponsible behavior of the SADE management in the Vajont and other businesses. Indro Montanelli, the most influential Italian journalist and a vocal anticommunist, attacked L'Unità and denied any human factor: L'Unità and other leftist newspapers were dubbed "jackals, speculating on pain and on the deads", and the catastrophe was attributed only to natural causes and God's will. ^[7]

Democrazia Cristiana, the party of prime minister Giovanni Leone, accused the PCI of profiteering on the tragedy for political interest. Leone promised to bring justice to the people killed in the disaster, but when only a few months after he lost the leadership of the government he became the head of the SADE's lawyers team, who managed to avoid compensation to at least 600 victims and greatly reduce the payments to survivors. ^[8]

The DC's newspaper, La Discussione, stated that the disaster was a "misterious act of god's love", in an article that was strongly criticized by L'Unità ^[9]

Apart the journalists discussions and the cover-ups by sources neat the government's political area, it quickly became clear that there had been flaws in the geological assessments and abundant warnings about the likelihood of a disaster, which had been consciously ignored by SADE, ENEL and the government.

The trial was moved by authority to L'Aquila, near Rome, thus preventing public participation, and finished with mild punishments for a few of the SADE and ENEL engineers. One SADE engineer (Mario Pancini) committed suicide in 1968. The government never sued SADE for damage compensation.

In engineering terms, subsequent analysis of the disaster has focused on the cause of the landslide. There remains ongoing debate about the contribution of rainfall, dam level changes and earthquakes as triggers of the landslide, as well as differing views about whether it was an old landslide that slipped further or a completely new one. ^[10]

There were a number of problems with the choice of site for the dam and reservoir: The canyon was steep sided, the river had undercut its banks, the limestone and clay-stone rocks that made up the walls of the canyon were inter-bedded with the slippery clay-like Lias and Dogger Jurassic period horizons and the Cretaceous period Malm horizon, all of which were inclined towards the axis of the canyon. In addition, the limestone layers contained many solution caverns which only became more saturated due to rains in September. ^[11]

Prior to the landslide that caused the over-topping flood, the creep of the regolith had been a rapid 0.4 inches per week. During September this creep reached 10.0 inches per day until finally, the day before the landslide, the creep was measured at 1 metre (40.0 inches).^[12]

Most of the survivors from the shores of the basin were displaced and prompted to move in a newly built village, Vajont, in the plains about 50 kilometres away. Those who insisted to get back to their mountain life in Erto and Casso were strongly discouraged. Longarone and other villages in the Piave valley were rebuilt in a modern style, with factories added.

The government exploited the disaster to promote the industrialization of the North-East of Italy. A law allowed privileged loans, public contributions and ten years of no taxes to the survivors of the disaster who wanted to restart their commercial activities, but it also allowed major companies from the rest of the Venice region to buy these privileges from the survivors (usually shattered and unlearned people, either very old or very young) for a few hundred euros in today's terms, and to use them to receive public funding for several tens of million of euros to build plants elsewhere. Among the corporations which reaped these benefits there are Zanussi (now owned by Electrolux), Ceramica Dolomite (now owned by American Standard), Confezioni SanRemo, SAVIC (now owned by Italcementi). ^[13]

Also, many compensation measures made no difference between people who had been actually struck by the disaster, and people who just lived nearby. As a result, much of the compensation went to people who had suffered almost no damage at all and who became rich thanks to the tragedy, thus creating a negative public image for the actual survivors.

Regarding the basin, a pumping station was installed to keep the lake at a constant level, and the bypass gallery was later lengthened beyond the dam to let the water flow down to the Piave valley. The dam is being maintained and is still in place, unaffected by the tragedy; there are no plans yet to exploit the plant in any way. Since 2002, it is possible to visit the dam.

The tragedy deeply saddened both Italy and the world, but was quickly archived as one of the prices paid for Italy's impressive economic growth in the 1950's and 1960's.

Interest rose again thanks to the theatrical tale by Marco Paolini and Gabriele Vacis, "Il racconto del Vajont", which gained an unexpected success when televised in Italy in 1997. In 2001, a movie was released about the Vajont disaster, "Vajont, La diga del disonore" ("Vajont, the dam of dishonour") or "La folie des hommes" (in France), starring Michel Serrault and Daniel Auteuil. It has also featured in the documentary series Disasters.^[14]

• List of reservoirs and dams
• Seiche
• Tsunami
• St. Francis Dam
• List of natural disasters by death toll

• Franco Mantovania and Claudio Vita-Finzi, 'Neotectonics of the Vajont dam site', Geomorphology, Vol. 54, Issues 1-2, 2003, pp 33-37.
• David Petley, Landslide information: The Vajont (Vaiont) Landslide, 2001, retrieved January 2008.
• Suburban Emergency Management Project (SEMP), 'Epic Vajont Dam Disaster, Italy, 1963: Manmade or Natural?', Biot #373: June 17, 2006, retrieved January 2008.

Wikimedia Commons has media related to Vajont Dam.

• Il disastro del Vajont Template:It icon
• Comitato Sopravissuti del Vajont Template:It icon
• Vajont: Almost a Greek Tragedy Template:En icon
• Vajont, La diga del disonore at IMDb
• Vajont Dam photos and virtual field trip (University of Wisconsin), retrieved 2009-07-01

46°16′02″N 12°19′44″E / 46.26722°N 12.32889°E / 46.26722; 12.32889